Modern automobiles have painted finishes which are far more lustrous than the finishes found on automobiles manufactured even a few years back. This effect is achieved in part by using techniques which produce a paint surface that is far smoother at the microscopic level than techniques providing a less lustrous finish. Such highly lustrous finishes do, however, have disadvantages: contamination of the surface with dust and grit is much more difficult to control, and any scratches or mars are more noticeable and more unsightly.
An unrelated but concurrent development in the automobile industry is the increased popularity of dual color schemes on autos. The preferred method for applying such dual color schemes is as follows: (a) the entire auto is painted one color; (b) a premasked decal, such as a pinstripe, is applied to the auto at the desired location as a break line; (c) the surface of the auto is masked off on one side of the break line; (d) a second paint coat of a different color is applied on the other side of the break line; (e) the finish is baked; and (f) both the premask from the decal and the mask from the other side of the break line are removed.
It is difficult to perform this two-color painting procedure when a smooth surface is also being imparted to the paint to achieve a lustrous finish. This difficulty arises from inadequacies in the premasked decals currently available. A paper premask is currently available, but when a decal having a paper premask is pressed against the painted surface, the textured paper imprints its textured pattern into the decal. Because of this, the decal will have a marred appearance when applied to an automobile having a smooth paint finish.
It is conceivable that a smooth plastic sheeting could be used as a premask. This would not have a texture that would mar the decal, but would result in other disadvantages. Foremost would be the problem of contamination with dust and grit because of the buildup of a static charge during assembly of such a premasked decal.
A premasked decal is itself assembled from two components: a decal transfer portion, and a premask portion. Both of these are typically in the form of large rolls or spools of raw material. The premask portion, before assembly, is adhered to a strippable release liner. During assembly, the decal transfer portion and the premask portion are each continuously unwound, the premask release liner is continuously stripped away, the premask is continuously adhered to the decal, and the premasked decal transfer is continuously wound onto a takeup spool. Individual premasked decals are then cut from the takeup spool. A similar procedure is employed when the decal transfer portion is provided in sheet form.
Because the premask would be plastic, and since the premask release liner would also be plastic, the continuous stripping of one from the other will cause the accumulation of a static charge. This will cause grit and dust to adhere to the premask, and will mar the decal surface when the premask is adhered thereto. Moreover, these mars become more noticeable when noncontaminated portions of the decal are smoothed by the plastic premask, or when the decal is smoothed by heat in the car paint baking process. If the premasked decal is not processed through a paint baking cycle, such dust and grit would still interfere with attempts to smooth the decal surface by other means, such as by press polishing.
Nothing in the prior art provides a premasked decal which overcomes these difficulties.
U.S. Pat. No. 4,337,107 to Eshleman discloses an abrasion-resistant transfer laminating sheet material comprised of, in the following sequence, a strippable carrier, an epoxy-terminated silane polymer layer, a pressure sensitive adhesive, and a strippable release sheet. Acrylic auto paint surfaces are among the suggested substrates to be transfer laminated by this invention, but the invention is directed solely toward imparting protective surfaces, and does not teach how the strippable carrier could be used as a premask, or how the carrier could be altered to solve the aforementioned masking problems. Indeed, the use of the term "carrier" establishes that this disclosure is not directed to premasks at all.
U.S. Pat. Nos. 4,211,809 and 4,211,810 to Barta disclose a self-adhering transfer material comprised of, in the following order, a "picture paper" layer, a separating layer, the transferable design layer, an adhesive layer, and a silicone or foil layer. U.S. Pat. No. 3,065,120 to Avelar discloses a dry transfer decal comprised of, in the following order, a dry release sheet, a transfer structure, and a paper slip sheet. None of these patents have anything to do with premasked decals.
Still other patents are available which describe improved plastic laminates, but these again have nothing to do with premasked decals. Exemplary is U.S. Pat. No. 3,899,621 to Willdorf, which discloses a security film for shatter-proofing windows having a vapor deposited aluminum layer, and which is comprised of at least one polyurethane layer interposed between at least a pair of polyester layers. Also exemplary is U.S. Pat. No. 4,329,396 to Kropp, which discloses a corrosion-resistant reflective or transparent reflective sheet material which may be adhered to a windowpane.
It is accordingly an object of the present invention to provide a premasked decal which can be applied to a substrate without marring the decal.
More specific objects of the invention are to provide a premasked decal which will neither attract dust and grit during assembly nor impart a texture to the decal surface during application to a substrate.
Further objects of the invention are to provide a premasked decal which can be easily aligned on a background of any color, and which will provide an easily observable indication that the premask layer has not been removed from the decal transfer.